Sag resistant, cast acoustical ceiling tile and method for making the same

摘要

A sag resistant, cast acoustical ceiling tile which has a mineral wool core and a starch binder and which has a formaldehyde resin impregnated paper backing. A kraft paper backing which has been impregnated with a melamine formaldehyde resin has been found particularly effective in providing sag resistance in high temperature, high humidity conditions such as encountered in Pacific Rim countries. A method has been developed to manufacture the sag resistant, cast acoustical ceiling tile wherein water is applied to the paper backing prior to machining and painting to provide a tile which has a relatively flat initial plane position.